Personal vaporizers are devices that turn a liquid into a vapor so that a person can inhale the vapor. Many personal vaporizers are relatively small (pocket-sized or pen-sized), battery-powered, and use an atomizer or heater to vaporize the liquid. The personal vaporizer converts a liquid into a vapor that is inhaled. Personal vaporizers are inherently portable and come in a variety of forms.
An exemplary personal vaporizer is found in the Pen Kits available from Verso PV of Fort Collins, Colo. Pictures and instructions for use of the Verso personal vaporizer are shown in Appendix A. Additional examples of commercially available personal vaporizers include the liquid personal vaporizers from Atmos; the vaporizer pen from VapeToys, O.penVAPE and many others. Personal vaporizers include electronic flameless vapor inhaler units that may simulate a cigarette.
Personal vaporizers are often used as alternatives to smoked tobacco products, such as cigarettes, cigars, or pipes. Inhaled doses of vapor provide a physical sensation similar to smoking. However, because a personal vaporizer is typically electrically powered, no tobacco, smoke, or combustion is usually involved in its operation. For portability, and to simulate the physical characteristics of a cigarette, cigar, or pipe, a personal vaporizer may be battery powered. In addition, a personal vaporizer may be loaded with a nicotine bearing substance and/or a medication bearing substance. The personal vaporizer may provide an inhaled dose of nicotine and/or medication by way of the heated and atomized substance. Thus, personal vaporizers are sometimes referred to as electronic cigarettes, or e-cigarettes. However personal vaporizers are not limited to delivering nicotine or acting as a cigarette substitute. To the contrary, they may be used to administer flavorants, medicinal agents, or other substances that are vaporized and then inhaled.
Personal vaporizers can be filled with liquid compositions to be vaporized. Such liquid compositions generally include a liquid base and one or more other components. Typical personal vaporizer liquid bases include propylene glycol, glycerol, or PEG-400, and they are primarily intended to function with the addition of water-soluble additives.
Besides delivering nicotine or being used as a cigarette substitute, personal vaporizers have been used to provide a vapor from solutions of actives (such as ingredients, flavors and/or medicinal compounds) in a base of propylene glycol, which is the standard liquid base for e-cigarettes. Propylene glycol is non-toxic and safe for daily consumption. When heated, propylene glycol produces a smooth vapor, when inhaled, with a mildly sweet taste. When a solution of propylene glycol, actives, and flavorings are mixed and heated, the vapor becomes infused with the added ingredients, taking on a variety of flavors and therapeutic uses. Ingredients such as nicotine and flavorings such as “Peach Flavor” from LorAnn Oils have been used in liquid compositions for personal vaporizers.
However manufacturers of personal vaporizer liquids have had difficulty creating a stable emulsion containing oil-soluble compounds. The personal vaporizer liquids presently on the market typically have an off palate and/or do not perform well, due to a waxy ballast discharge, terpenoid loss, separation from base liquid, the presence of self-emulsifying agents creating a range of viscosity, and unstable and unrefined emulsions, respectively. Other emulsifiers will thermally decompose and produce carcinogenic byproducts with intolerable flavor.
Personal vaporizers can also be used for the delivery of cannabinoids or cannabis extracts. The National Institutes of Health (NIH) released a review of the scientific data concerning potential therapeutic uses for marijuana in 1997. In that review, the NIH found that marijuana may have beneficial medicinal effects and recommended that researchers develop alternative dosage forms for the drug, such as a “smoke free” inhaled delivery system. Various studies have documented therapeutically beneficial medicinal uses of the major active component of marijuana, delta-9-tetrahydrocannabinol (THC). See U.S. Pat. No. 6,713,048, entitled “Δ9 tetrahydrocannabinol (Δ9 THC) solution metered dose inhalers and methods of use”. Makers of personal vaporizer liquids containing oil-soluble compounds, or resins, have had difficulty creating a stable emulsion. The personal vapor liquids presently on the market typically have an off palate and/or do not perform well, primarily due to a waxy ballast discharge, separation from base liquid, the presence of self-emulsifying agents creating a range of viscosity, and unstable and unrefined emulsions.
WO 02/064109 discloses a method of preparing an extract from medicinal cannabis. The process comprises (1) a heating step to decarboxylate the acid form of the cannabinoids to their neutral form; (2) a first extraction with a specified volume of liquid carbon dioxide for 6-8 hours; and (3) a step to reduce the proportion of non-target materials, referred to as winterization, which precipitates out waxes. More specifically, step (1) comprises heating chopped cannabis at 100-150° C. for sufficient time to allow decarboxylation. Step (2) comprises CO2 extraction using supercritical conditions. Step (3) comprises conducting an ethanol precipitation at −20° C. for 24 hours and removing the waxy material by filtration.
U.S. Pat. No. 6,946,150 describes formulations containing cannabinoids for administration via a pump action spray. In particular, the invention relates to pharmaceutical formulations, for use in administration of lipophilic medicaments via mucosal surfaces, comprising: at least one lipophilic medicament, a solvent and a co-solvent, wherein the total amount of solvent and co-solvent present in the formulation is greater than 55% wt/wt of the formulation and the formulation is absent of a self emulsifying agent and/or a fluorinated propellant.
U.S. Pat. No. 7,344,736 also describes extraction of cannabinoids from cannabis using liquid carbon dioxide, as well as winterization to remove waxy material. The patent relates preparation of a botanical drug substance (BDS) for incorporation into a medicament. It also relates to a BDS of given purity, for use in pharmaceutical formulations. In particular it relates to BDS comprising cannabinoids obtained by extraction from cannabis. For example, the patent discusses an extraction process where a botanical raw material is decarboxylated by heating to approximately 105° C. for 15 minutes, followed by approximately 145° C. for a minimum of 55 minutes for THCA and 90 minutes for CBDA. An extraction with food grade liquid carbon dioxide (CO2) for up to 10 hours at a pressure of approximately 60 bar+/−10 bar and 10° C.+/−5° C. The CO2 is removed by depressurization to recover crude extract. A “Winterization” step is performed in which the crude extract is dissolved in ethanol followed by chilling solution (−20° C.+/−5° C. for up to 52 hours) to precipitate unwanted waxes. The unwanted waxy materials are then removed by cold filtration using a 20 μm (micron) filter. Ethanol and water are removed from the filtrate by thin film evaporation under reduced pressure (60° C.+/−2° C., with vapor at 40° C.+/−2° C./172 mbar and 72 mbar+/−4 mbar). This yields the botanical drug substance.